Exhaust Manifolds and are you Pleased

[FlagCraig]

Who has put their original exhaust manifolds (instead of headers) back on after a complete engine rebuild and are you happy?

Reason I'm asking is we are at the final stages of my stroker (505) rebuild and the original exhaust manifolds we took off look fantastic. I'm just questioning the investment of headers when it's never going to see the track. Will any loss of HP (20-40?) without headers be that noticeable when street driven.

Also we are using the original 915 heads that have been machined and ported. Thx.

 

[69Bee]

I had no issues with mine. Leaking headers suck, and wanted to avoid that problem. I couldn't afford high dollar headers as a PFC...

PS.. Be careful with that "Peg Leg" engine stand. That heavy engine can easily tip over, and quite honestly, fully dressed, approaches the 750 lb rating!

 

[dadsbee]

I got the header thing out of me when I was 18.... some 38 years ago ! Don't have the energy for chasing header leaks, etc at this age. Hated it back then as well. Besides, stocks look nicer IMHO ! ..now don't anyone tell me my heater hoses are supposed to cross!

 

[Lazerwolf]

Don't think there is a right answer on this question. It's up to your personal taste and application.

I have a 74 Charger, rebuild 400 with E-Street heads and voodoo cam so only making maybe 400 HP. I ordered a complete TTI exhaust from Chicago Connection. I already had factory HP manifolds on the car so they suggested not going with headers. Their reason was headers are louder, create more heat under hood and only give you 10-20 HP at higher RPMS, which you'll never notice on the street. Are they correct? I don't know, never tested on a dyno. I kept the factory HP manifolds with 2 1/2" TTI exhaust with H pipe and am very happy with that. I love to cruise in the car and like you, don't do any racing, so consider that also.

 

[dla4567]

Stock manifolds here. No stroker, 440 cu in, 492 hp, 512ft/lb. would I gain much hp with headers?? Yes, but I’m not racing and I’ve got plenty of power for a street car. Plus, there is always somebody faster. I quit trying to have the fastest car in town a long time ago. (My neighbors street car has 4000 hp).

 

[33 IMP]

Nicks garage posted a test of headers vs. manifolds on a 471 stroked hemi. If I remember right, manifolds cost something like sixty to eighty hp. It is on you tube.
I'm curious, why build a stroker and port the heads , and then put a cork up it's wazoo? For a cruiser with manifolds, a 440 should have been plenty.

 

[ksurfer2]

My engine (440 6bbl) is at the machine shop right now undergoing a stroker build. One of my requirements for the build was that it needed to perform with the stock HP manifolds and 6bbl set up. My goal is to have an engine that looks stock but runs like hell. Motor is scheduled to come back next week. I'll let you know how it turned out.

 

[Johnpat]

Unless your going racing all the time you will
never miss any HP.
It doesn't help until you hit 3500RPM or above.

 

[66383]

I had no issues with mine. Leaking headers suck, and wanted to avoid that problem. I couldn't afford high dollar headers as a PFC...

PS.. Be careful with that "Peg Leg" engine stand. That heavy engine can easily tip over, and quite honestly, fully dressed, approaches the 750 lb rating! TRUE, I tipped one over with a small block about 10 yrs. ago on a rough garage floor!

 

[Cranky]

There are ways to make headers not leak. Just got to learn what the secrets are. A flat and straight flange is the first clue. My first car got headers and they leaked but my second and all the rest didn't. A 14" or longer flat smooth file is your friend (not even sure if a 16" is made). And I never did make the gasket surface super smooth. Make sure the gasket surface on the head is flat and smooth too and make sure the ports match with the headers. A big inch engine with ported heads etc just doesn't make much sense to me unless you really want cast manifolds and then spend the money to extrude hone them.

 

[33 IMP]

When my numbers matching 440 needed freshening I put a 511 in the car, with mild port work, pump gas compression, and a (approx) 300-.500 hyd cam. I used the stock manifolds and exhaust.
By the time the stroker "came on the cam" the manifolds plugged up the power., even with 4.10 gears. The stroker sure didn't feel any stronger than the 440, the perception was that it wouldn't pull a fat girl off a tricycle.

 

[Cranky]

Unless your going racing all the time you will
never miss any HP.
It doesn't help until you hit 3500RPM or above.

I have to disagree with the 3500 rpm deal. Any time you free up the flow, it's going to let the engine breathe easier even down low especially a stroker big cube engine and I sure would notice the loss of HP with a capped up/restricted exhaust system......

 

[beanhead]

Who has put their original exhaust manifolds (instead of headers) back on after a complete engine rebuild and are you happy?

Reason I'm asking is we are at the final stages of my stroker (505) rebuild and the original exhaust manifolds we took off look fantastic. I'm just questioning the investment of headers when it's never going to see the track. Will any loss of HP (20-40?) without headers be that noticeable when street driven.

Also we are using the original 915 heads that have been machined and ported. Thx.
View attachment 676614

With a stroker like that, for running around on the street it's gonna make plenty of power with manifolds. Headers will definitely pick it up all through the rpm range. You don't need to go big and expensive, heck I've had great luck with the cheap hooker comp headers...noticed quite a difference from those over manifolds on the same engine. Just depends on what you want, as headers do you have their drawbacks. Me personally, I like headers because I want the extra power and I like the sound.

 

[69roadr]

The sound Factor alone is worth it get the headers

 

[oldbee]

Either way IMHO, if HP manifolds; don’t go crazy on the camshaft. Read the arengineering.com tech pages. Very interesting.

 

[BSB67]

I have manifolds and happy with them.

One way of looking at it is: "what am I giving up" Another way of looking at it is: "can I make the power I want"

For me, I had a performance goal and was able to get there with manifolds.

To maximize power potential with manifolds, cam selection is important.

 

[Coronutcase]

In my opinion (and it's just that), I think if you don't install headers, you'll always wonder.... what could have been. If you went to the trouble and expense of porting along with the machining, your engine is most likely begging for headers!

Your heads are flat because you just had them machined. A set of new TTI headers with Remflex gaskets should seal up just fine for a long time. And, the TTI headers will actually fit correctly and look great. As for sound, you can control that with many options of mufflers that will still provide good flow.

Whether you use manifolds or headers, either way, I would go with X or H-Pipe in your system.

It's your car and you should do what you feel most comfortable with. This is only what I would do if it was mine. By the way, your engine looks great... love the bluish turqoise correct color!

 

[33 IMP]

I agree with bsb67, cam selection is Very important. Andy F many years ago did a cam test on his own car with a 440 with manifolds. The wrong cam absolutely killed drivability and power (if memory serves). Maybe pm him, see if he can help with a cam selection.

 

[Glenwood]

I had hp manifolds on a fresh rb and hated them. Retained too much heat for me. I switched to dougs ceramic coated and love them. Much less heat, easier access to the plugs and I like the look. They are not any louder then it was with manifolds.

 

[FitzyB5]

https://www.hemmings.com/magazine/mus/2017/07/How-Hot-The-Hemi-/3750986.html
This is the 426 Hemi I purchased from Don at RAD machine and transplanted in my 67 Coronet RT tribute convertible. You can see dyno results with factory headers vs racing headers. Not a huge difference.